If one ton of coal costs $36, which gives an energy cost of $0.006 per kWh

And one barrel of oil costs $70, which gives an energy cost of $0.05 per kWh

And one cubic foot of gas costs $0.008, which gives an energy cost of $0.03 per kWh

Then a 4 kW solar panel system providing energy for an average ranch-style home and costing $25,000 and lasting about 20 years would provide about 120,000 kWh for the life of the system (depending on climate) and cost about $0.21 per kWh.

You can see that solar power is still more currently more expensive than other fuel sources.